"Top-up" generator for backup batteries

[thsolar]

I'm designing a home with a grid-tied PV system. The system is designed with 52 panels, 3 solar edge batteries and inverters tbd.
In the event of a protracted winter power outage (less sun, cloudy days) and the batteries not fully charging by the end of the solar day - without adding a large, installed genset to completely take over when the batteries are low - how can I add an input from a small 1500-3000kW portable generator to "top up" the house backup batteries over night to make sure that they are at full capacity in the morning?

 

[wattmatters]

I'm designing a home with a grid-tied PV system.

The grid is a fantastic generator.

 

[CRenner]

Most inverters have a generator input, but it is usually 240v.
You need a battery charger that will work on 120v.

 

[meetyg]

Maybe get an AC to DC charger ?

 

[Delmar]

I would look for an “all-in-one” inverter that has inputs for grid power, solar panels and generator. You can program the AIO to automatically switch between the inputs as required. Will also act as a UPS for autonomous operation.

 

[DIYrich]

Chargeverter. Although, might be overwhelmed by 3000kw.

 

[seneysolar]

Charging with suitcase generator?

Anyone charging their battery bank with a small suitcase generator? (Under 2500w). I see lots of folks on here using big generators but thats alot of fuel... I have a plug wired on my Aims 4k inv/charger and i use my yamaha 2000 for charging. I have 4 trojan L-16's in series for 24v. I realize...

diysolarforum.com

 

[hwy17]

Solar edge 400v batteries makes this difficult.

With a 48v bank you just use an AC/DC charger appropriately matched to the generator's output.

 

[wattmatters]

I'd have thought you'd be restricted to using Solaredge inverters with Solaredge batteries.

It's a grid-tied system, so why the need for a generator?

 

[dougbert]

Solar edge 400v batteries makes this difficult.

With a 48v bank you just use an AC/DC charger appropriately matched to the generator's output.

yes, this poses a BIG problem - this will force you to use solaredge everything

 

[hwy17]

It's a grid-tied system, so why the need for a generator?

For power outages.

 

[wattmatters]

For power outages.

Is that not what the OP's grid-tied batteries and PV system are for?

OK, if there is a multi-day outage during a period of poor insolation then I get it. But the OP hasn't returned to say, so who knows?

 

[hwy17]

Is that not what the OP's grid-tied batteries and PV system are for?

OK, if there is a multi-day outage during a period of poor insolation then I get it. But the OP hasn't returned to say, so who knows?

He said in the event of a protracted outage and cloudy weather, so I'm pretty sure.

 

[wsaharem]

Look at EG4's chargeverter. This doesn't connect directly to the inverter, but can be connected to the battery and you can control voltage and current for the charging. I'm using this for the same purpose as OP wants. (extended outage without grid as the backup).

 

[wattmatters]

He said in the event of a protracted outage and cloudy weather, so I'm pretty sure.

Good point.

Given the OP's choice of Solaredge battery they need to read this document from Solaredge about use of generator for charging during grid outages:

https://knowledge-center.solaredge.com/sites/kc/files/se-solaredge-inverter-generator-compatibility-with-energy-hub-and-backup-interface-application-note-eng.pdf

 

[hwy17]

Good point.

Given the OP's choice of Solaredge battery they need to read this document from Solaredge about use of generator for charging during grid outages:

https://knowledge-center.solaredge.com/sites/kc/files/se-solaredge-inverter-generator-compatibility-with-energy-hub-and-backup-interface-application-note-eng.pdf

Good find. It almost looks on first skim like it can't charge the batteries from generator.

 

[thsolar]

Maybe get an AC to DC charger ?

I'm going to think about this. I would like to have the generator look like an alternate PV input at the inverter.

 

[thsolar]

Chargeverter. Although, might be overwhelmed by 3000kw.

You're right. On the other hand, with 52 panels, I'm seeing 18kw - 20kw at the inverter in full sun.

 

[thsolar]

I'd have thought you'd be restricted to using Solaredge inverters with Solaredge batteries.

It's a grid-tied system, so why the need for a generator?

Yes, I will be in the

He said in the event of a protracted outage and cloudy weather, so I'm pretty sure.

Correct!

 

[meetyg]

I'm going to think about this. I would like to have the generator look like an alternate PV input at the inverter.

That's more complicated. Why not just get an AC to DC charger that will directly connect to your battery? You could use an Anderson connector to connect the charger to the battery when needed.